November 14, 2012

Impaired Cognition Not Related To Migraine-associated Brain Changes

by editor

NIH/National Institute of Neurological Disorders and Stroke

NIH-funded study tracks nearly 300 people for 9 years

Women with migraines did not appear to experience a decline in cognitive ability over time compared to those who didn't have them, according to a nine-year follow up study funded by the National Institutes of Health.

The study also showed that women with migraine had a higher likelihood of having brain changes that appeared as bright spots on magnetic resonance imaging (MRI), a type of imaging commonly used to evaluate tissues of the body.

"The fact that there is no evidence of cognitive loss among these women is good news," said Linda Porter, Ph.D., pain health science policy advisor in the Office of the Director at the National Institute of Neurological Disorders and Stroke (NINDS), which provided funding for the study. "We've known for a while that women with migraine tend to have these brain changes as seen on MRI. This nine-year study is the first of its kind to provide long-term follow-up looking for associated risk."

"An important message from the study is that there seems no need for more aggressive treatment or prevention of attacks," said Mark C. Kruit, M.D., Ph.D., one of the principal investigators, and a neuroradiologist from Leiden University Medical Center, the Netherlands, which led the study. Dr. Kruit and associates evaluated MRIs for changes in the white matter, brainstem, and cerebellum that appeared on the scans as bright spots known as hyperintensities. Previous studies have shown an association between such hyperintensities and risk factors for atherosclerotic disease, increased risk of stroke and cognitive decline.

The extent of MRI brain findings increased slightly with time, according to the population-based study that tracked 286 men and women with and without migraines.

Men with migraines had no greater incidence of such changes compared with age-and sex-matched controls. Although female participants with migraine in this study were more likely to have hyperintensities, there was no clear relation to the frequency of migraine attacks, the type of migraine or how they were treated.

Standardized measures of cognitive abilities such as memory, concentration, and attention did not show significant losses among people with migraine-associated lesions compared to those without migraine. The brain changes that give rise to the bright spots seen on MRI are unknown. More research is needed to find out if these are related to ischemia and ischemic stroke risk, according to the researchers.

The findings, which appear in the Nov. 14th issue of the Journal of the American Medical Association, update observations from an investigation conducted in 2000 showing that women with migraines were more likely than age-matched controls to have scattered areas of white matter changes on MRI scans. That initial population-based study, known as the Cerebral Abnormalities in Migraine, an Epidemiological Risk Analysis (CAMERA-1), screened and evaluated 295 men and women with migraine and compared them with 140 age- and sex-matched controls. In that study, people who had more frequent migraines also had a higher incidence of changes seen on their MRIs, suggesting that migraine attacks could have a cumulative effect.

In the current investigation, known as CAMERA-2, researchers sought to tease out differences between men and women, and to find out whether the type of migraine was associated with an increase in the volume of new white matter changes relative to that seen in the initial study. Researchers reassessed 286 of the original participants. Among them, 114 had migraine with aura, 89 had migraine without aura, and 83 were controls.

Compared with baseline, women with migraines were twice as likely as those without such attacks to have an increase in the volume of diffuse white matter changes. However, this increase was still very small, said one of the study's investigators, Lenore J. Launer, Ph.D., chief of the Neuroepidemiology Section at the National Institute on Aging (NIA).

CAMERA-2 also showed no correlation between new brain lesions and migraine frequency. This finding may be due to the fact that structural changes to the brain arise not with each new migraine attack, but are the result of an ongoing process that occurs even during periods between attacks, Dr. Kruit said.

The study participants aged, making it difficult to tease out brain changes that are specifically attributable to migraine. That is because age, as well as hypertension and diabetes, are also known risk factors for white matter changes, Dr. Launer explained. Sixty percent of control females without migraine showed progression of white matter lesions as compared to 77 percent of those with migraine.

These findings add to the increasing amount of data that migraine, particularly in women, is progressively related small blood vessel changes, the researchers wrote in the paper.